Developing a distributed electronic health-record store for India

The DIGHT project is addressing the problem of building a scalable and highly available information store for the Electronic Health Records (EHRs) of the over one billion citizens of India

An analysis of minimax facility location problems with area demands /

The unconstrained model, and its solution technique can be easily modified to solve the limiting case where all facilities are fixed points, and also the case when metric constraints are added.Examples are solved to show the impact of assuming area demands, the conflicting nature of the minimax and minisum criteria and to illustrate the solutions techniques developed.A minimax objective function constrained by a bound on the total average cost of servicing all existing facilities (minisum function) is then discussed. Using duality properties, this problem is shown to be equivalent to another model which minimizes the minisum function subject to a bound on the same minimax function. This last problem proves to be easier to solve, and a specialized solution technique is developed. The resulting solutions are nondominated solutions in relation to the two criteria involved. Another way to generate nondominated solutions is by combining the two functions into a weighted sum. The constrained criterion method is shown to be superior both analytically and practically.Most probabilistic facility location problems investigated to date were variations of the generalized Weber formulation. In this research, several single facility minimax location models are analyzed, where both the weights and the locations of the existing facilities are random variables. The demand points are uniformly distributed over rectangular areas, the rectilinear metric is used and the weights are assumed to be independently distributed random variables. Two unconstrained probabilistic models are analyzed and compared to the centroid formulation, it is seen that the probabilistic models are sensitive to deviations from optimal solutions. An expected value criterion formulation is also presented along with lower and upper bound approximating functions

Methodology and Software for Interactive Decision Support

These Proceedings report the scientific results of an International Workshop on "Methodology and Software for Interactive Decision Support" organized jointly by the System and Decision Sciences Program of IIASA and The National Committee for Applied Systems Analysis and Management in Bulgaria. Several other Bulgarian institutions sponsored the workshop -- The Committee for Science to the Council of Ministers, The State Committee for Research and Technology and The Bulgarian Industrial Association. The workshop was held in Albena, on the Black Sea Coast. In the first section, "Theory and Algorithms for Multiple Criteria Optimization," new theoretical developments in multiple criteria optimization are presented. In the second section, "Theory, Methodology and Software for Decision Support Systems," the principles of building decision support systems are presented as well as software tools constituting the building components of such systems. Moreover, several papers are devoted to the general methodology of building such systems or present experimental design of systems supporting certain class of decision problems. The third section addresses issues of "Applications of Decision Support Systems and Computer Implementations of Decision Support Systems." Another part of this section has a special character. Beside theoretical and methodological papers, several practical implementations of software for decision support have been presented during the workshop. These software packages varied from very experimental and illustrative implementations of some theoretical concept to well developed and documented systems being currently commercially distributed and used for solving practical problems

On the design of a cost-efficient resource management framework for low latency applications

The ability to offer low latency communications is one of the critical design requirements for the upcoming 5G era. The current practice for achieving low latency is to overprovision network resources (e.g., bandwidth and computing resources). However, this approach is not cost-efficient, and cannot be applied in large-scale. To solve this, more cost-efficient resource management is required to dynamically and efficiently exploit network resources to guarantee low latencies. The advent of network virtualization provides novel opportunities in achieving cost-efficient low latency communications. It decouples network resources from physical machines through virtualization, and groups resources in the form of virtual machines (VMs). By doing so, network resources can be flexibly increased at any network locations through VM auto-scaling to alleviate network delays due to lack of resources. At the same time, the operational cost can be largely reduced by shutting down low-utilized VMs (e.g., energy saving). Also, network virtualization enables the emerging concept of mobile edge-computing, whereby VMs can be utilized to host low latency applications at the network edge to shorten communication latency. Despite these advantages provided by virtualization, a key challenge is the optimal resource management of different physical and virtual resources for low latency communications. This thesis addresses the challenge by deploying a novel cost-efficient resource management framework that aims to solve the cost-efficient design of 1) low latency communication infrastructures; 2) dynamic resource management for low latency applications; and 3) fault-tolerant resource management. Compared to the current practices, the proposed framework achieves 80% of deployment cost reduction for the design of low latency communication infrastructures; continuously saves up to 33% of operational cost through dynamic resource management while always achieving low latencies; and succeeds in providing fault tolerance to low latency communications with a guaranteed operational cost

Integrated model for Multi-criteria Supplier Selection and Order Allocation Problem

Abstract. This paper discusses an integrated model of selecting suppliers and order allocation for a company that wishes to decide the quantity to be ordered from each supplier on the basis of some qualitative criteria. Since each supplier may have a different performance with respect to these criteria, an integration of analytical hierarchy process and linear program model is proposed to solve the problem in two stages. In the first stage, suppliers are evaluated based on qualitative criteria to consider both tangible and intangible factors in choosing the best suppliers. The output of this stage is the final score of each supplier. In the second stage, a linear programming model is proposed to placing the optimum order quantities among them such that the total final scores of suppliers become maximum. The mathematical programming model is validated through numerical analysis, and the computation result shows that the model is effective and applicable. Keywords: supplier selection, order allocation, multiple criteria decision making, analytical hierarchy process, linear programming

Desenvolvimento de ferramentas de apoio multicritério à decisão em problemas de localização

Tese de doutoramento, Estatística e Investigação Operacional (Análise de Sistemas), Universidade de Lisboa, Faculdade de Ciências, 2014Nesta tese, apresenta-se um Sistema de Apoio à Decisão, desenvolvido e implementado com o objectivo de apoiar a tomada de decisão em problemas de localização bicritério que envolvam preocupações ambientais. O apoio é dado em duas fases interactivas distintas, acreditando que os métodos interactivos são a melhor forma de abordar os modelos multicritério. Na primeira fase, recorre-se a um procedimento de optimização combinatória para obter, de forma progressiva e participativa, qualquer solução não dominada dos modelos de localização bicritério implementados. Nesta primeira fase interactiva, destaca-se a importância de ser possível utilizar um Sistema de Informação Geográfica, integrado no Sistema de Apoio à Decisão, para a obtenção de dados relevantes para os modelos em causa, especialmente aqueles que requerem mais preocupações relativamente aos impactos ambientais. O uso do Sistema de Informação Geográfica, ao longo de todo o processo de decisão, também permite uma visualização apelativa e real das soluções interactivamente obtidas. Na segunda fase, caso seja necessário, usa-se a posteriori uma ferramenta de análise multiatributo para estudar em detalhe as soluções de compromisso provenientes da primeira fase. Esta ferramenta corresponde a uma implementação interactiva simples do método conjuntivo, fazendo uso de um gráfico radar como base do procedimento. A ferramenta proposta pretende contornar o problema da compensação, evitando uma agregação intercritério. O método de análise inerente à ferramenta não exige qualquer transformação ou normalização, de forma a assegurar a comparabilidade entre os critérios. De modo a descrever e a validar as potencialidades e as funcionalidades do SABILOC – o Sistema de Apoio à Decisão desenvolvido e implementado, explora-se um caso de estudo de um problema real relativo à localização de estações de transferência de resíduos.In this thesis, we present a two-phase interactive Decision Support System aimed at supporting decision-making concerning bicriteria location models in which the facilities to be located could have environmental impacts. The decision support is provided through two interactive phases, believing that interactive methods are the best way to deal with multicriteria models. First, a combinatorial optimization procedure to obtain, in a progressive and participatory way, any non-dominated solution of the bicriteria location models implemented, is used. In this first phase, we highlight that a Geographic Information System, embedded into the Decision Support System, can be used to obtain relevant data for the models concerned, especially those considering environmental issues. The Geographic Information System also allows, throughout the decision process, visualizing in an appealing and real way the solutions interactively obtained. Next, if necessary, a multiattribute a posteriori analysis tool could also be employed in order to analyze in detail a set of compromise solutions from the first phase. This one stands for a simple interactive implementation of the conjunctive method making use of a radar chart as basis for the procedure. The tool proposed is intended to circumvent the problem of compensation, avoiding aggregation inter-criteria. To use the method inherent to the tool proposed, it is not required any transformation or normalization to insure the comparability between criteria. In order to describe and validate the potentialities and functionalities of SABILOC – the Decision Support System developed and implemented, we present a case study of a real world problem applied to waste transfer station siting.Fundação para a Ciência e a Tecnologia (FCT, Programa de Apoio à Formação Avançada de Docentes do Ensino Superior Politécnico - PROTEC

Problemas de localização-distribuição de serviços semiobnóxios: aproximações e apoio à decisão

Doutoramento em Gestão IndustrialA presente tese resulta de um trabalho de investigação cujo objectivo se centrou no problema de localização-distribuição (PLD) que pretende abordar, de forma integrada, duas actividades logísticas intimamente relacionadas: a localização de equipamentos e a distribuição de produtos. O PLD, nomeadamente a sua modelação matemática, tem sido estudado na literatura, dando origem a diversas aproximações que resultam de diferentes cenários reais. Importa portanto agrupar as diferentes variantes por forma a facilitar e potenciar a sua investigação. Após fazer uma revisão e propor uma taxonomia dos modelos de localização-distribuição, este trabalho foca-se na resolução de alguns modelos considerados como mais representativos. É feita assim a análise de dois dos PLDs mais básicos (os problema capacitados com procura nos nós e nos arcos), sendo apresentadas, para ambos, propostas de resolução. Posteriormente, é abordada a localização-distribuição de serviços semiobnóxios. Este tipo de serviços, ainda que seja necessário e indispensável para o público em geral, dada a sua natureza, exerce um efeito desagradável sobre as comunidades contíguas. Assim, aos critérios tipicamente utilizados na tomada de decisão sobre a localização destes serviços (habitualmente a minimização de custo) é necessário adicionar preocupações que reflectem a manutenção da qualidade de vida das regiões que sofrem o impacto do resultado da referida decisão. A abordagem da localização-distribuição de serviços semiobnóxios requer portanto uma análise multi-objectivo. Esta análise pode ser feita com recurso a dois métodos distintos: não interactivos e interactivos. Ambos são abordados nesta tese, com novas propostas, sendo o método interactivo proposto aplicável a outros problemas de programação inteira mista multi-objectivo. Por último, é desenvolvida uma ferramenta de apoio à decisão para os problemas abordados nesta tese, sendo apresentada a metodologia adoptada e as suas principais funcionalidades. A ferramenta desenvolvida tem grandes preocupações com a interface de utilizador, visto ser direccionada para decisores que tipicamente não têm conhecimentos sobre os modelos matemáticos subjacentes a este tipo de problemas.This thesis main objective is to address the location-routing problem (LRP) which intends to tackle, using an integrated approach, two highly related logistics activities: the location of facilities and the distribution of materials. The LRP, namely its mathematical formulation, has been studied in the literature, and several approaches have emerged, corresponding to different real-world scenarios. Therefore, it is important to identify and group the different LRP variants, in order to segment current research and foster future studies. After presenting a review and a taxonomy of location-routing models, the following research focuses on solving some of its variants. Thus, a study of two of the most basic LRPs (capacitated problems with demand either on the nodes or on the arcs) is performed, and new approaches are presented. Afterwards, the location-routing of semi-obnoxious facilities is addressed. These are facilities that, although providing useful and indispensible services, given their nature, bring about an undesirable effect to adjacent communities. Consequently, to the usual objectives when considering their location (cost minimization), new ones must be added that are able to reflect concerns regarding the quality of life of the communities impacted by the outcome of these decisions. The location-routing of semi-obnoxious facilities therefore requires to be analysed using multi-objective approaches, which can be of two types: noninteractive or interactive. Both are discussed and new methods proposed in this thesis; the proposed interactive method is suitable to other multi-objective mixed integer programming problems. Finally, a newly developed decision-support tool to address the LRP is presented (being the adopted methodology discussed, and its main functionalities shown). This tool has great concerns regarding the user interface, as it is directed at decision makers who typically don’t have specific knowledge of the underlying models of this type of problems

Optimization of Gas Transmission Networks under Energetic and Environmental Considerations

The transport of large quantities of natural gas (NG) is carried out by pipelinenetwork systems across long distances. Pipeline network systems include one orseveral compressor stations which compensate for pressure drops. A typical net-work today might consist of thousands of pipes, dozens of stations, and manyother devices, such as valves and regulators. Inside each station, there can be sev-eral groups of compressor units of various vintages that were installed as the ca-pacity of the system expanded. The compressor stations typically consume about3 to 5% of the transported gas. It is estimated that the global optimization ofoperations can save considerably the fuel consumed by the stations. Hence, theproblem of minimizing fuel cost is of great importance. This study presents amathematical formulation for NG transport through pipelines and compressors byconsidering the mass and energy balance equations on the basic elements of a di-dactic network from the literature. First, a deterministic optimization procedure isimplemented. The objective of this formulation is the fuel minimization problemin the compressor stations for a fixed gas mass flow delivery. A second example isdevoted to the simultaneous consideration of gas mass flow delivery maximizationand fuel consumption minimization. In that case, two procedures are compared:a genetic algorithm coupled with a Newton-Raphson procedure and the scalariza-tion method of ?-constraint. In both monobjective and biobjective cases, a studyof carbon dioxide (CO2) emissions is carried out. The Pareto front deduced fromthe biobjective optimization can be used either for identifying the minimum andmaximum network capacity in terms of CO2 emissions and mass flow delivery or for a given mass flow delivery for determining the minimal CO2emissions froman appropriate operating of the compressor stations

Domination and Decomposition in Multiobjective Programming

During the last few decades, multiobjective programming has received much attention for both its numerous theoretical advances as well as its continued success in modeling and solving real-life decision problems in business and engineering. In extension of the traditionally adopted concept of Pareto optimality, this research investigates the more general notion of domination and establishes various theoretical results that lead to new optimization methods and support decision making. After a preparatory discussion of some preliminaries and a review of the relevant literature, several new findings are presented that characterize the nondominated set of a general vector optimization problem for which the underlying domination structure is defined in terms of different cones. Using concepts from linear algebra and convex analysis, a well known result relating nondominated points for polyhedral cones with Pareto solutions is generalized to nonpolyhedral cones that are induced by positively homogeneous functions, and to translated polyhedral cones that are used to describe a notion of approximate nondominance. Pareto-oriented scalarization methods are modified and several new solution approaches are proposed for these two classes of cones. In addition, necessary and sufficient conditions for nondominance with respect to a variable domination cone are developed, and some more specific results for the case of Bishop-Phelps cones are derived. Based on the above findings, a decomposition framework is proposed for the solution of multi-scenario and large-scale multiobjective programs and analyzed in terms of the efficiency relationships between the original and the decomposed subproblems. Using the concept of approximate nondominance, an interactive decision making procedure is formulated to coordinate tradeoffs between these subproblems and applied to selected problems from portfolio optimization and engineering design. Some introductory remarks and concluding comments together with ideas and research directions for possible future work complete this dissertation

Multi-objective optimization for ecodesign of aerospace CFRP waste supply chains

Composites have been increasingly used in different applications in the last decade, especially in aerospace due to their high strength and lightweight characteristics. Indeed, the latest models of Airbus (A350) and Boeing (B787) have employed more than 50 wt% of composites, mainly Carbon Fibre Reinforced Polymers (CFRP). Yet, the increased use of CFRP has raised the environmental concerns about their end-of-life related to waste disposal, consumption of non-renewable resources for manufacturing and the need to recycle CFRP wastes. In this study, a generic model is developed in order to propose an optimal management of aerospace CFRP wastes taking into account economic and environmental objectives. Firstly, a life-cycle systemic approach is used to model the environmental impacts of CFRP recycling processes focusing on Global Warming Potential (GWP) following the guidelines of Life Cycle Assessment (LCA). The whole supply chain for recycling CFRP pathways is then modelled from aircraft dismantling sites to the reuse of recycled fibres in various applications. A multi-objective optimisation strategy based on mathematical programming, -constraint and lexicographic methods with appropriate decisionmaking techniques (M-TOPSIS, PROMETHEE-GAIA) has been developed to determine CFRP waste supply chain configurations. Various scenarios have been studied in order to take account the potential of existing recycling sites in a mono-period visions as well as the deployment of new sites in a multi-period approach considering the case study of France for illustration purpose. The solutions obtained from optimisation process allow developing optimal strategies for the implementation of CFRP recovery with recycled fibres (of acceptable quality) for the targeted substitution use while minimising cost /maximising profit for an economic criterion and minimising an environmental impact based on GWP